328 Review of M. O. Des Murs' ' Oologie Ornithologique/ 



Next in order in M. Des Murs' treatise, and forming its second 

 part, comes the " Determination of Oological Characters/' doubt- 

 less the most difficult part of his task, taking into considera- 

 tion the wide variation to which specimens, produced by the 

 same species — nay, the same individual bird — are subject. In 

 this division our author lays down as the three principal points 

 to be attended to in the examination of eggs, — 1st, their form ; 

 2ndly, the nature of their shell; and, 3rdly, the colours which 

 distinguish them. With respect to the first of these points — 

 Form — M. Des Murs seems to consider it as of most importance, 

 and therefrom separates eggs into six categories, which he thus 

 denominates : — 



(1.) The spherical, best exemplified by those of the Owls. 



(2.) The oval, under which he includes those of the Diuraal 

 Raptores. 



(3.) The cylindrical, as illustrated by the eggs of the Ptero- 

 clina. 



(4.) The ovate, of which those of the Phasianida serve as a 

 familiar instance. 



(5.) The ovdiconical, which comprehends by far the greater 

 nimiber of the eggs of the Scolopacidce. 



(6.) The elliptical, as shown in the case of the genus Podiceps. 



Reserving, for the present, all criticism upon the nomencla- 

 ture proposed, we agree with the author, that under one or 

 another of these heads may be fairly enough comprised the egg 

 of every known species of bird, though it will be understood 

 that we are compelled to restrict the illustration of the definitions 

 to the most meagre limits, and to omit the many exceptional 

 cases which will readily occur to the veriest tyro in oology. We 

 must, however, add here one remark of M. Des Murs (pp. 65, 

 66):— 



" Si I'on veut, apres cela, examiner d'une maniere generale et 

 un peu plus methodique, la repartition de ces formes dans la 

 classe des Oiseaux, on en aura une idee par le tableau suivant, 

 dresse, pour exemple, conformement h I'enseignement de M. 

 Isid. GeofFroy Saint-Hilaire : — 



